Cementing well pipe in stages



April 28, 1964 .w. P. ORR 3,130,783

CEMENTING WELL PIPE IN STAGES 7 Filed Aug. 2, 1962 2 Sheets-Sheet 1INVENTOR.

WILLIS P, ORR,

BFMMM ATTORNEY.

w. P. ORR

CEMENTING WELL PIPE IN STAGES 2 Sheets-Sheet 2 INVENTOR. L a /wATTORNEY.

April 28, 1964 Filed Aug. 2, 1962 United States Patent Oflfice 3,130,783Patented Apr. 28, 1964 a corporation of Delaware Filed Aug. 2, 1962,Ser. No. 214,300 2 Claims. (Cl. 16626) This invention concerns apparatusfor use in a technique for cementing well pipe in a borehole in two ormore stages, and in particular, it concerns a staging tool or toolsarranged along the length of a well pipe in a manner such that carryingout of a stage cementing operation is facilitated.

Stage cementing of well pipe has important advantages in many wells oversingle column cementing. It reduces the possibility of breaking down aweak formation with the high cementing pressures required to lift a longcolumn of cement; it minimizes cement contamination during long columncementing; it reduces the quantity of cement required when it is desiredto cement widely separated or spaced intervals; and it is useful inplacing a cement sheath as a substitute for surface casing.

However, these advantages in operations are offset when presentlyavailable staging techniques and tools are used, for in these techniquesto complete the Well after stage cementing operations, it is necessaryto drill out cement, plugs, and the stage tool or tools left in the wellpipe.

Thus, the staging tool of the invention overcomes disadvantages in theuse of available tools by eliminating the necessity of drilling out thetool and by leaving the well pipe full of displacing fluid instead ofhaving a portion of the well pipe filled with cement. In the arrangementof the apparatus, the entire length of the well pipe is accessible forwork-over operations.

In known stage cementing techniques also, the rubber plugs used to spotthe stage cement remain in the well pipe and are difiicult to drill out.In the present technique, no plug is left in the well pipe, andconsequently, drilling out of it prior to cementing in the later stagesis eliminated.

The staging tool of the invention permits cementing of upper sands;cementing olf of a water sand; and placing of cement as a substitute forsurface casing.

Thus, a primary object of the present invention is to provide animproved stage cementing tool and a stage cementing technique for usetherewith.

In brief, the cement staging tool comprises a tubular housing or mandreladapted to be arranged in a well pipe and having circular ports or flowpassageways therein, each containing fluid pressure releasable plugmeans initially closing off fluid communication between the interior andexterior of said well pipe through said mandrel and releasable toestablish fluid communication between the interior and exterior of saidwell pipe through said mandrel when sufiicient fluid pressure is appliedagainst said plug means from within said well pipe; and longitudinallymovable positive closure means arranged within said mandrel adapted toclose off fluid communication through said ports after said plug meanshave been released when in an upper position and adapted to permit fluidcommunication through said ports after said plug means have beenreleased when in a lower position.

The above object and other objects and advantages of the invention willbe apparent from a more detailed description thereof when taken with thedrawings wherein:

FIG. 1 is a vertical, partly-sectional view of the staging tool of theinvention;

FIG. 2 is a view similar to that shown in FIG. 1, except the plugs shownin FIG. 1 having been released are being replaced with balls toillustrate a step in the operation which assures that all of the portshave opened.

FIG. 3 is a view taken on lines 33 of FIG. 2; and

FIG. 4 is a schematic illustration of a typical use of the staging toolof FIGS. 1 to 3.

For a more complete description of the invention, reference now is madeto the drawings in greater detail.

As seen in FIG. 1, the staging tool comprises a sub or mandrel 10provided with threaded end portions 12 and 13 for threadedly connectingmandrel 10 in a well pipe 14 (see FIG. 4), which in turn is supported ina borehole 15 from a wellhead 16.

Mandrel 10 is provided with a series of (preferably four) laterallyspaced-apart circular ports 17 (see FIG. 3 also). Each port initiallycontains a plug 18 which is provided with a seal 19 for closing off thespace between plug 18 and the Wall of the port. Plugs 18 are releasablyattached to mandrel 10 by means of shear pins 20. A sliding sleeve valve21, having upper and lower positions and a series of laterallyspaced-apart openings 22, each circularly configured and larger thaneach port 17, is arranged within mandrel 10 such that each opening 22 iscircumferentially or laterally aligned with one of the ports 17. Theupper end of sleeve valve 21 is split to form a plurality of expansiblefingers 23, which have formed thereon latching shoulders 24. The lowerend of sleeve valve 21 is indented to form a square shoulder 25, whichinitially rests on a square shoulder 26 formed on the interior wall ofmandrel 10. Sleeve valve 21 is notched above shoulder 25 and belowopenings 22, as at 27. Also, the inner wall of mandrel 10 is slottedabove shoulder 26, as at 28, and a square shouldered snap ring 29 isarranged in the slot. When sleeve valve 21 is in its lower position, asseen in FIGS. 1 and 2, notch 27 is adjacent slot 28, and openings 22 andports 17 are vertically aligned. Sealing elements 30 and 31 are providedon the inner wall of mandrel 10 above and below ports 17. Snap ring 29engages beveled shoulder notch 27 when sleeve valve 21 is in its lowerposition and temporarily locks the sleeve valve in this position. In theupper position of sleeve valve 21, not shown, square shoulder 25 restson square shouldered snap ring 29 to permanently lock sleeve valve 21 inthis position. Also, in this position, openings 22 are positioned aboveupper sealing element 30, which seals off fluid communication betweenopenings 22 and ports 17.

The operation of a two-stage cementing technique utilizing one stagingtool for a Well containing only one long pipe string is illustrated inFIG. 4, and this operation now will be described.

To cement the first stage, the well is conditioned as required, and thefirst stage cement is pumped from cement truck 35 through conduits 36and 37 into well pipe 14, which is provided with a conventional cementshoe 38. A volume of cement sufficient to cement off an interval 39 ispumped down well pipe 14 past the stage tool and through cement shoe 38and up the annulus between the wall of borehole 15 and well pipe 14, asindicated at 40, the predetermined volume of cement being followed by acement top plug 41 and follow-up fluid pumped by pump 42 through conduit37 until plug 41 is positioned atop cement shoe 38, as illustrated. Wellfluid in the annulus between the well pipe and the borehole wall 15 isdisplaced upwardly through the annulus to the earths surface.

During the first stage cementing, the stage tool is arranged asillustrated in FIG. 1; that is, the sleeve valve is open and releasableplugs 18 maintain the ports 17 in mandrel 10 closed.

The second stage cement slurry is now placed in the annulus byfirst'pumping fluid by means of pump 42 into well pipe 14 by way ofconduit 37, and additional pressure, 1000 to 3000 p.s.i. above thepressure used for the first stage cementing job, is applied to fractureshear pins 20 of each of the releasable pump-out plugs 18 and flushthese plugs from ports 17.

To insure that all of the plugs have been flushed out of ports 17, portclosure balls 9 are placed in the fluid circulated down well pipe 14,through openings 22 and one or more of the ports 17 and up the annulusbetween well pipe 14 and borehole wall 15 to seal off openings 22, whichalso seals off ports 17. The balls insure that all of ports 17 open. Forexample, if only two plugs 18 are flushed out, two balls 9 lodge in thetwo openings 22 aligned with the two ports 17, from which these plugswere flushed, which permits fluid pressure to increase and force releaseof the remaining plugs. When the balls fill all of the ports 17, thefluid pressure builds up, assuring that all of the pump-out plugs 18have been flushed out. FIGS. 2 and 3 show three balls positioned inports 17. When all of the balls are positioned in the ports, fluidpressure on the balls is released, and the balls drop to the bottom ofthe well pipe 14 (see FIG. 4). FIG. 2 also illustrates a ball (dottedlines) dropping from its position in a port 17.

Once the balls have been removed from their positions in ports 17, thesecond stage cement slurry from cement truck 35 is pumped throughconduits 36 and 37 into well pipe 14 through openings 22 and 17 into theannulus between well pipe 14 and the wall of borehole 15. The desiredvolume of cement for the second stage designated 45 is followed bydisplacing fluid pumped into well pipe 14 by means of pump 42. Thenwhile pressure is maintained within well pipe 14, sleeve valve 21 ismoved to its upper, closed position by lowering a wire line tool, notshown, into well pipe 14 to adjacent sleeve valve 21 to engage shoulder24 and raise sleeve valve 21 upwardly until shoulder 25 is latched bysnap ring 29. Sliding sleeve valve 21 can be locked in this position,since there is no further need for opening this valve.

By use of this technique the well pipe 14 is only left with cementdisplacing fluid following the cementing operation. The well pipe isfully open. There are no plugs or tools or cement to drill out foradditional cementing stages. The advantages of closing the stage tool bymoving sleeve 21 up instead of down are: (1) the tight fitting wiperplug used to displace the first stage cement cannot even inadvertentlymove sleeve 21 to its closed position; and (2) swabbing operationssubsequent to cementing do not tend to open the stage tool by movingsleeve 21 upwardly; the uppermost shoulder in mandrel prevents furtherupward movement of sleeve 21 when it is in the closed position.

Although in the foregoing description of the invention only the settingof a surface sheath of cement was described, other second-stagecementing operations may be performed. Additionally, although only atwo-stage cementing operation using one well pipe and one staging toolwas described to illustrate the invention, three or more cementingstages using additional staging tools may be carried out. When more thanone staging tool is used, each tool is positioned adjacent the place thecement is to be spotted, and to prevent the upper tool from frac turingshear pins 20 prematurely, the relative strengths of the shear pins ofeach tool may be increased from the lowermost to the uppermost tools.Also, cementing operations may be carried out using the staging tools inmultiple tubingless completions, in which case one or more of the toolswould be arranged in each of several strings of easing.

Having fully described the nature, operation, elements, and objects ofmy invention, I claim:

1. Apparatus for use in stage cementing of well pipe in a boreholecomprising: a mandrel adapted to be connected in said well pipe andprovided with at least two laterally spaced-apart circular ports; fluidpressure releasable plug means initially secured in each port; aslidable sleeve valve longitudinally movable within said mandrel andprovided with at least two openings, each of which is larger than eachof said ports; sealing means arranged between said sleeve valve and saidmandrel above and below said ports and said openings when said ports andsaid openings are aligned; said openings and said ports being alignedwhen said sleeve valve is in a lower position to fluidly communicate theinterior of said sleeve and said ports, said sleeve when in an upperposition being adapted to close off fluid communication between theinterior of said sleeve valve and said port; and stop means on saidmandrel adapted to limit further downward movement of said sleeve valveWithin said mandrel when said sleeve valve is in its lower position; andmeans for locking said sleeve valve in its upper closed position.

2. A method for use in stage cementing of well pipe in a borehole usingapparatus which comprises: a mandrel adapted to be connected in saidwell pipe and provided with at least two laterally spaced-apart circularports; a fluid-pressure releasable plug releasably secured in each ofsaid ports; a slidable sleeve longitudinally movable within said mandreland having at least two openings therein larger than said ports andaligned with i said ports when said valve is in a lower position tofluidly communicate the interior or" said sleeve and said ports; sealingmeans arranged between said sleeve and said mandrel adapted when saidsleeve is in an upper position to close off fluid communication betweenthe interior of said sleeve and said ports; and means for locking saidsleeve in its upper closed position comprising the steps of: pumpingfluid into said well pipe and increasing fluid pressure within said wellpipe until at least one of said fluid pressure releasable plugs isreleased and flushed from its port; circulating fluid down said wellpipe and through said openings in said sleeve and said mandrel ports andup the annulus surrounding said well pipe; adding balls to said fluid toseal off said ports with said balls after the ports have been opened byflushing out the plugs to assure opening of all of the ports; releasingthe fluid pressure to permit the balls lodged in the ports to drop outof them into the bottom of the borehole; pumping a cement slurry intosaid well pipe and through said openings in said sleeve and said mandrelports and depositing said cement slurry in the annulus surrounding thewell pipe; and then while maintaining pressure in said well pipe movingsaid sleeve to its closed position to seal ofl said mandrel ports.

References Cited in the file of this patent UNITED STATES PATENTS2,603,293 Lynes July 15, 1952 2,659,438 Schnitter Nov. 17, 19532,836,246 Hoch May 27, 1958

1. APPARATUS FOR USE IN STAGE CEMENTING OF WELL PIPE IN A BOREHOLECOMPRISING: A MANDREL ADAPTED TO BE CONNECTED IN SAID WELL PIPE ANDPROVIDED WITH AT LEAST TWO LATERALLY SPACED-APART CIRCUIT PORTS; FLUIDPRESSURE RELEASABLE PLUG MEANS INITIALLY SECURED IN EACH PORT; ASLIDABLE SLEEVE VALVE LONGITUDINALLY MOVABLE WITHIN SAID MANDREL ANDPROVIDED WITH AT LEAST TWO OPENINGS, EACH OF WHICH IS LARGER THAN EACHOF SAID PORTS; SEALING MEANS ARRANGED BETWEEN SAID SLEEVE VALVE AND SAIDMANDREL ABOVE AND BELOW SAID PORTS AND SAID OPENINGS WHEN SAID PORTS ANDSAID OPENINGS ARE ALIGNED; SAID OPENINGS AND SAID PORTS BEING ALIGNEDWHEN SAID SLEEVE VALVE IS IN A LOWER POSITION TO FLUIDLY COMMUNICATE THEINTERIOR OF SAID SLEEVE AND SAID PORTS, SAID SLEEVE WHEN IN AN UPPERPOSITION BEING ADAPTED TO CLOSE OFF FLUID COMMUNICATION BETWEEN THEINTERIOR OF SAID SLEEVE VALVE AND SAID PORT; AND STOP MEANS ON SAIDMANDREL ADAPTED TO LIMIT FURTHER DOWNWARD MOVEMENT OF SAID SLEEVE VALVEWITHIN SAID MANDREL WHEN SAID SLEEVE VALVE IS IN ITS LOWER POSITION; ANDMEANS FOR LOCKING SAID SLEEVE VALVE IN ITS UPPER CLOSED POSITION.